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Date:   Fri, 31 Jul 2020 13:56:49 -0300
From:   Jason Gunthorpe <jgg@ziepe.ca>
To:     Steven Sistare <steven.sistare@oracle.com>
Cc:     Matthew Wilcox <willy@infradead.org>,
        "Eric W. Biederman" <ebiederm@xmission.com>,
        Anthony Yznaga <anthony.yznaga@oracle.com>,
        linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        linux-mm@kvack.org, linux-arch@vger.kernel.org, mhocko@kernel.org,
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        peterz@infradead.org, esyr@redhat.com, christian@kellner.me,
        areber@redhat.com, cyphar@cyphar.com
Subject: Re: [RFC PATCH 0/5] madvise MADV_DOEXEC
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On Fri, Jul 31, 2020 at 12:11:52PM -0400, Steven Sistare wrote:
> > Your preservation-across-exec use-case might or might not need the
> > VMA to be mapped at the same address.  
> 
> It does.  qemu registers memory with vfio which remembers the va's in kernel
> metadata for the device.

Once the memory is registered with vfio the VA doesn't matter, vfio
will keep the iommu pointing at the same physical pages no matter
where they are mapped.

Jason